Split the cases (first Time) 0n my RD 250 B, now putting her back together but not sure about where or where not to put assembly lube. Particularly on the crank, if at all. Any help would be appreciated.
I put a bit of 2stroke oil on the main. big end and small end bearings and basically give the cylinder a wipe with a paper towel with a bit of oil on it during assembly. Basically very little oil as I want to make sure the bearings are lubed while giving my rings the best chance of seating.
Thanks, that helps
Put a good 2 stroke oil in it AFTER you assemble the cases.
Chuck
Supertune, are you saying to put two stroke oil where the crank is? sorry for the dumb question
Quote from: hank22 on April 04, 2020, 12:04:48 AM
Supertune, are you saying to put two stroke oil where the crank is? sorry for the dumb question
Yes, just a bit into each main bearing, the rod bearing, etc. before you assemble the top end. Lube the piston pin and bearing and lube the piston and cylinder walls before you assemble the top end. Also put a thin smear of grease on the base gasket on both sides (any standard grease will do, just talking a translucent thin smear). This helps prevent the gaskets from sticking when the top end comes off.
The reason you want to assemble the case halves first is simple. As you flip the top and bottom halves around to tighten the bolts, any excess oil will start draining through the cases and can mess up the threebond sealer. Ask me how I know. :bang:
Thanks for clearing that up
All good information! At the risk of muddying the waters, I remember reading about the idea of assembling two-stroke top ends DRY, as in no oil on cylinder walls, pistons or rings. The premise was that the lubricating oil arrived with the fuel charge relatively immediately and oil already in the ring lands could cause the rings to stick, hindering break-in. I've never been brave enough to try it. Has anyone heard of this before, and what does the community think about it?
no and no.
Ive never heard of it or tried it.
Me? i always oil the rings a bit and some here and there on the bearings and wipe the cyl walls. I have a small squeeze container of injector oil, works fine.
^^^^^What I do^^^^^
I have heard of people blowing machines up without lubing anything.
In the BMW community (which I once was part of) it was common to assemble the cylinders with just a drop of oil on each piston skirt. Me? I was too chicken to do that...
Lyn Garland
Quote from: Striker1423 on April 04, 2020, 12:57:33 PM
I have heard of people blowing machines up without lubing anything.
I doubt that no assembly oil was ever the reason for them blowing up. Much more likely something else was wrong.